Testers such as the 93000 SOC (System On a Chip) Series tester offered by Agilent Technologies, Inc. provide rapid testing of complex circuitry. Such testers can produce massive quantities of sequential test data, with the test results contained in the sequential test data being associated with relatively few indicators as to what kind of testing led to the creation of particular ones or sets of the test results. Simple ways to infer relationships between the test results are therefore useful.